// Copyright 2020 The Evcxr Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::ops::Deref;

use evcxr_runtime;
use image;

pub trait ImageDisplay {
    fn evcxr_display(&self);
}

impl<P: image::Pixel<Subpixel = u8> + 'static, C> ImageDisplay for image::ImageBuffer<P, C>
where
    C: Deref<Target = [P::Subpixel]>,
{
    fn evcxr_display(&self) {
        let mut buffer = Vec::new();
        image::png::PngEncoder::new(&mut buffer)
            .encode(&**self, self.width(), self.height(), P::COLOR_TYPE)
            .unwrap();
        evcxr_runtime::mime_type("image/png").bytes(&buffer);
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn rgb_image() {
        let img = image::ImageBuffer::from_fn(10, 10, |x, y| {
            if (x as i32 - y as i32).abs() < 3 {
                image::Rgb([0, 0, 255])
            } else {
                image::Rgb([0, 0, 0])
            }
        });
        use super::ImageDisplay;
        img.evcxr_display();
    }

    #[test]
    fn gray_image() {
        let img = image::ImageBuffer::from_fn(10, 10, |x, y| {
            if (x as i32 - y as i32).abs() < 3 {
                image::Luma([255])
            } else {
                image::Luma([0])
            }
        });
        use super::ImageDisplay;
        img.evcxr_display();
    }
}
